Elon Musk and Grimes welcomed a second baby into the world via a surrogate, according to a Vanity Fair cover story.
The child's name is Exa Dark Sideræl Musk, but they call her "Y."
The name has a special meaning to the couple. Grimes said Exa is a computer term and Sideræl is “the true time of the universe, star time, deep space time, not our relative earth time.”
The child was born in December, according to the article.
Grimes said Exa was not her first choice for a baby name. In the article, she says she was "fighting for Odysseus Musk.”
Musk and Grimes are no strangers to uncommon baby names. They named their first child X Æ A-12. He goes by "X."